miaou-server/templates/network-manager/50-miaou-resolver

#!/bin/bash

if [[ "$2" == "up" ]]; then

    chattr -i /etc/resolv.conf

    ACTIVE_CONNECTION=$(nmcli -g NAME connection show --active | head -n1)
    ACTIVE_DEVICE=$(nmcli -g DEVICE connection show --active | head -n1)
    BRIDGE=$(ip addr show lxdbr0 | grep "inet\b" | awk '{print $2}' | cut -d/ -f1)
    GATEWAY=$(ip route | head -n1 | grep default | cut -d' ' -f3)
    logger -t NetworkManager:Dispatcher -p info "on $ACTIVE_DEVICE:$ACTIVE_CONNECTION up , change resolver to $BRIDGE,$GATEWAY"
    nmcli device modify "$ACTIVE_DEVICE" ipv4.dns "$BRIDGE,$GATEWAY"

    if ! grep nameserver /etc/resolv.conf | head -n1 | grep -q "$BRIDGE"; then
        # sometimes, nmcli generates wrong order for namespace in resolv.conf, therefore forcing connection settings must be applied!
        logger -t NetworkManager:Dispatcher -p info "on $ACTIVE_DEVICE:$ACTIVE_CONNECTION nameservers wrong order detected, therefore forcing connection settings must be applied"
        nmcli connection modify "$ACTIVE_CONNECTION" ipv4.ignore-auto-dns yes
        nmcli connection modify "$ACTIVE_CONNECTION" ipv4.dns "$BRIDGE,$GATEWAY"
        logger -t NetworkManager:Dispatcher -p info "on $ACTIVE_DEVICE:$ACTIVE_CONNECTION nameservers wrong order detected, connection reloaded now!"
        nmcli connection up "$ACTIVE_CONNECTION"
    else
        logger -t NetworkManager:Dispatcher -p info "on $ACTIVE_DEVICE:$ACTIVE_CONNECTION nameservers look fine"
    fi

    chattr +i /etc/resolv.conf

else
    if [[ "$2" == "connectivity-change" ]]; then
        ACTIVE_DEVICE=$(nmcli -g DEVICE connection show --active | head -n1)
        logger -t NetworkManager:Dispatcher -p info "on $ACTIVE_DEVICE connectivity-change detected"
    fi
fi